1. Field of the Invention
The present invention relates to vehicle environmental control systems and methods and, more particularly, toward methods and systems for automatically sensing fogging conditions, and instituting appropriate measures to prevent fogging and to remove window fog should fog be present.
2. Description of Related Art
In conventional automobile control systems, application of remedial measures to combat fogging of the vehicle windows is manually instituted by the vehicle passengers. Naturally, such remedial measures, which primarily consist of activating a vehicle heating, ventilation, and air conditioning (HVAC) system into a defrost mode of operation, are employed after a fogging condition has developed, and typically require some time to alleviate the fogging condition. As will be appreciated, such systems are not suitable for automatic control, and do not anticipate impending fogging conditions.
In vehicles incorporating an automatic HVAC control system, it has been proposed to sense internal and external conditions to determine whether fogging is likely. Such known systems include a glass temperature sensor and a humidity sensor. The glass temperature sensor is affixed to an internal surface of the windshield glass, and the humidity sensor is disposed adjacent to the windshield glass. The system uses the sensed glass temperature and the sensed cabin humidity to determine whether a possible fogging condition exists, and actuates the HVAC system in response thereto. Unfortunately, such automated systems require additional sensors, which are expensive to purchase and require significant amounts of labor to install and electrically connect to the HVAC controller.
Therefore, there exists a need in the art for a method and system for anticipating fogging conditions within a vehicle cabin that is less expensive, that does not require additional sensors, and which will provide improved response to, and prevention of, fogging conditions.